Has anybody built Beng's Danni Steam engine.

Hi Brian, I stumbled across this stream of consciousness a couple of months ago. I was then and still am in the process of building a Danni engine and was very interested to hear about your progress and problems. It all sounded very familiar. I'm lucky to have a (small) Optimum OPTI BF16V mill, which is brilliant. Having bought the mill after I bought the pre-milled Danni kit, I thought I might have a go making a twin cylinder version, milling my own frame, etc. So that's what I'm doing, making the single and twin alongside each other. In the next week or two I plan to mill the flats on the cylinders and expect to use either a 12mm or 20mm cuttter. I also am untrained in milling, but I figure a larger diameter cutter will give a smoother finish than (say) a 6mm one. By the way, I had thought, from the absence of your posts for many months, that you might have given up on the project. I'm so glad to see you're still at it - such is the resilience of the human spirit. Regards, Lawrie

Brian,

Thinking about it [until Jason comes along to show you how it's done]

With your small lathe, and vertical slide ... I would use a fly-cutter.

MichaelG.

Hello Stranger!

As Michael says it could be done with the flycutter that you already have if it is ground like I showed on 21/10/16 to miss the flanges.

If you do go with a milling cutter in 6mm there are two things to check.

1. do you have sufficient movement to cover the whole surface in one setting, you will need to be able to move 24mm (30-cutter dia) a bigger cutter or the flycutter will cover a wider area so you won't need to move the work as much.

2. 6mm cutters are often quite short so make sure nothing will hit.

Both are easily checked by holding a bit of 6mm bar and doing a run through.

Edited By JasonB on 22/06/2017 11:43:30

I doubt that I will get anywhere with the fly cutter ; I cannot get the shape correct.

Lawrie : yes, a larger diameter milling bit does make sense. A 12mm bit should do it in three passes.

Brian, i purchased one of those 'inexpensive' vertical slides from Hare & Forbes and found that the square nuts used in the T-slots would strip if the clamp screws were tightened up enough to firmly hold the workpiece. I made up some proper T-nuts out of square steel strip which gave me more than twice the thread depth and no more problems.

Hi Brian, yes, something like a 12mm diameter end mill should do the job for you. Spin it at about 400 to 800rpm and see how you go.

Hi Brian, Yeah I reckon a 12mm cutter is what I'll use. My approach is to take cuts of only about 0.5mm to 1.0mm deep at a time - nice and slow. That way you don't get a lot of stress and vibration - and for me 'time isn't of the essence.' Regards, Lawrie

Geoff : any chance of a photo of the T nuts you made ? How much thread have you put on them ?

Another holdup : I have spent the last two weeks moving house (wife's idea) and cleaning the old apartment to vacate standards. The new workshop has much more room than the old living room ; lots of cupboards and storage space.

The drill press seems a bit wobbly for some reason and that will have to be looked at. The lathe bench is firm and stable. I have spent the morning rereading this thread and working out where I am at. I don't even remember making some of these parts !

For Australian residents : Now that Miniature Steam are no longer selling bar stock, who are you buying your brass and gunmetal bronze from ? What is the smallest diameter gunmetal bronze that you can readily buy ?

Edited By Brian John on 25/07/2017 04:47:36

Edited By Brian John on 25/07/2017 04:50:50

Brian, the new workshop looks good. I buy my bronze and brass from Allied Bearings usually. Not sure how small they go down.

Thanks Peter, I was not aware that Allied Bearings sold that. I called them just now and they have some 1/2'' gunmetal bronze in stock which seems to be the smallest available. He said they do not keep brass and but they can get it in on special order. Is that what you ask them to do ?

The vertical mill slide arrived today and I have been watching some youtube videos on milling in the lathe. Some people seem to think that holding the milling bit directly in the lathe chuck is a bad idea and it should be held in a collet to avoid damaging the chuck. Is this correct ? What type of collet should be used ?

It won't damage the chuck, some say a 3-jaw won't hold the cutter as firmly as a collet but if you just take light cuts then it will be fine in the 3 jaw. That Minnie traction engine in my avitar had all the milling done on the lathe with cutters held in the 3-jaw

Trying to fit the vertical mill slide. I removed the top slide from my lathe. It looks like the supplied steel bush fits in the hole on the mill slide then using a washer and a M6 X 44mm socket cap it will be screwed onto the cross slide. Unfortunately I do not have an M6 x 44mm socket cap or an M6 X44mm bolt of any type so things will have to wait until I source that.

Am I on the right track here ?

Sorry : I should have taken a photo showing the hole in the mill slide which takes the bush.

Edited By Brian John on 29/07/2017 10:09:33

Edited By Brian John on 29/07/2017 10:10:39

To get you going why not use the long stud that is laying next to your tool post and a nut, may need a bit of scrap tube or a couple of larger nuts to use as spacers if the thread is too short.

Is there just one hole in the bottom of the slide casting?

Here it is with and without the bush :

Why did they make the bush so long ?

Edited By Brian John on 29/07/2017 10:46:51

by raising it up you will get more swing on an allen key allowing for the length of the short side of the key.

I'd definately try it using teh stud from teh toolpost and a packer if needed.

Wonder of wonders : Bunnings had some M6 X 45mm socket caps on the shelf. I used two washers to get a good fit and it looks like it is ready to use.

What sort of cuts should I be taking with equipment like this : 0.5mm or 0.25mm at a time ?

Do I lock the carriage in place like I would with parting off and remove Xmm from the whole face before unlocking and advancing the carriage to remove another Xmm ?

Or do I remove all the required 4mm from one part of the cylinder and then raise the mill slide to remove the next section.

These may seem like dumb questions but I have not done this before and I do not want to race in and break something.

Edited By Brian John on 30/07/2017 06:37:20

Hi Brian,

If you can, lock the parts that don't move while taking a milling cut. Since I don't know your lathe my advice is to start with a light cut and see how your equipment copes, you will soon get the hang of it.Take it a bit slow with light cuts to begin with and increase dept of cut and see how the lathe performs. Good luck.

Thor

Yes lock the carrage and vertical slide if it has a lock screw. Start with light cuts and see how the machine handles them, increase if it sounds OK.

I think I would take several cuts at each height setting stopping just short (0.25mm) of finished size. Then take a final cut with the carrage locked and just moving the vert slide about 1/3rd of the cutters dia until you have milled the whole face.